#include <stdio.h>
void main()
{
    int *p = 0;
    printf("p=%p,p=%d", p, p);

    int i = 10;
    int j = 100;
    int *p1= (int *)0x12ff78;
    *p1 = NULL;
    printf("p1=%d,*p1=%d\n",p1,*p1);
}